9. Forms of Surgical Deviations of the Intestinal System: Stomas

I. Surgical Deviations of the Intestinal System

• Surgical deviation: Alteration of the natural flow of intestinal content
• Forms: Stoma and bypass
• Purpose: Divert feces/gas, protect anastomosis, bypass obstruction, allow healing or palliate symptoms

Stoma

• Stoma: Surgically created opening of intestine to abdominal skin surface
• Function: External diversion of feces/gas; jejunostomy can provide enteral nutrition
• Duration: Temporary or permanent
• Output depends on segment → Colostomy more formed, ileostomy liquid/high output risk, jejunostomy mainly feeding access

Bypass

• Bypass: Rerouting intestinal content around a diseased/obstructed segment without bringing bowel to skin
• Indications: Morbid obesity, short bowel syndrome, obstructed/strictured bowel, palliative GI cancer, congenital anomalies
• Examples: Gastrojejunostomy, ileotransverse bypass, gastric bypass

II. Types of Stomas

1. End Stoma

• End stoma: Divided proximal bowel end is brought to the skin surface
• Colostomy: Colon opened to abdominal wall

• Common site: Sigmoid colostomy, usually LLQ
• Indications: Colorectal cancer, complicated diverticulitis, traumatic bowel injury, congenital anomalies, Hartmann surgery

• Ileostomy: Ileum opened to abdominal wall

• Characteristics: Liquid/semi-liquid stool → Dehydration and electrolyte imbalance risk
• Indications: IBD, familial adenomatous polyposis (FAP), bowel perforation/necrosis, bowel obstruction

• Jejunostomy: Jejunum opened to abdominal wall, usually for feeding

• Indications: Long-term enteral nutrition when upper GI is not functional, post-gastrectomy/esophagectomy, upper GI obstruction

2. Double-Lumen Stoma

• Loop stoma: Loop of bowel brought out and opened → Proximal + distal lumens visible in one stoma

• Indications: Temporary diversion, protection of distal anastomosis, healing of distal bowel/rectum
• Examples: Protective loop ileostomy after low anterior resection; temporary loop colostomy

• Double-barrel stoma: Both divided bowel ends are brought out as two separate stomas

• Proximal stoma: Functional fecal diversion
• Distal stoma: Mucus fistula
• Indications: Trauma, ischemia, perforation, severe contamination, temporary diversion before later re-anastomosis

III. Indications for Stoma Creation

Temporary Diversion

• Protect distal anastomosis, especially low colorectal/coloanal anastomosis
• Allow healing of distal bowel, rectum or perineal wound
• After trauma, perforation, ischemia or emergency resection when primary anastomosis is unsafe
• May be reversed after healing if distal bowel and patient condition allow

Permanent Diversion

• After abdominoperineal resection for rectal cancer
• Severe anal sphincter dysfunction or incontinence
• Incurable anorectal malignancy, pelvic radiation damage or non-reconstructable distal bowel

Emergency / Disease-Specific Indications

• Bowel obstruction, perforation with peritonitis, necrotic/gangrenous bowel
• Complicated diverticulitis, traumatic bowel injury, ischemic bowel
• IBD: Staged surgery for ulcerative colitis or Crohn disease, severe perianal disease
• FAP and selected congenital anomalies such as Hirschsprung disease or anorectal malformation

IV. Practical Considerations and Complications

Planning and Care

• Preoperative stoma marking is important for optimal placement
• Patient education: Pouch change, skin care, output monitoring, diet, hydration, warning signs
• Stoma nurse, psychological and social support are important for adaptation
• Some stomas are reversible; others are permanent depending on disease and distal bowel function

Complications

• Early: Ischemia/necrosis, bleeding, edema, retraction, leakage, skin irritation, obstruction/ileus
• Ileostomy-specific: High output → Dehydration, electrolyte imbalance, renal injury
• Late: Parastomal hernia, prolapse, stenosis, chronic skin damage, psychological/sexual/social problems